This invention is an improvement on the invention described in my U.S. patent application Ser. No. 717,192, titled "Human-Machine Interface Apparatus" and filed Aug. 24, 1976 now U.S. Pat. No. 4,071,691, issued Jan. 31, 1978 and incorporated herein in its entirety by reference. The present invention improves the orthogonality of field components in Human-Machine Interface Apparatus and further provides a means of correcting any nonlinearity in the phase field generated by one embodiment of the Human-Machine Interface Apparatus. The present invention improves the utility of the invention disclosed in my above-identified patent by simultaneously correcting for two sources of nonlinearity. Thus, when the invention is used to input information into a machine by a human, for example, nonlinearity of the field does not have to be compensated for by additional circuitry.
The method of generating and controlling electric fields described herein has wider potential usefulness, both for correcting field nonlinearities and for producing fields of predetermined nonlinear characteristics in two or three dimensions.